The present invention generally regards mechanical pencils and pens. More particularly, the present invention regards a mechanical pencil or pen that has a push-button to advance the lead or pen and a push-button to advance the eraser.
Mechanical pencils are discussed in various patents including U.S. Pat. No. 5,306,085 to Kobayashi et al., and U.S. Pat. No. 5,642,953 to Kobayashi et al., which discuss mechanical writing instruments including a mechanical pencil in combination with a ball point pen and an eraser. The eraser discussed in the Kobayashi references can be advanced and retracted by rotating the barrel around the eraser with respect to the remainder of the barrel.
U.S. Pat. No. 4,904,101 to Petterson and U.S. Pat. No. 5,015,111 to Petterson discuss mechanical pencils having erasers that are extended and retracted by angular displacement of a part of the barrel with respect to another part of the barrel.
U.S. Pat. No. 6,290,413 to Wang discusses a writing and/or erasing instrument having a slidable thrust device.
A mechanical pencil and a method for operating a mechanical pencil is provided. The mechanical pencil includes a barrel, a lead chamber, a first push-button, an eraser chamber, and a second push-button. The barrel includes a pencil-end, an eraser-end, and an outer surface. The lead chamber is situated in the pencil-end and holds a lead. The first push-button is situated on the outer surface and is coupled to the lead chamber. The eraser chamber is situated in the eraser-end and holds an eraser. The second push-button is situated on the outer surface and is coupled to the eraser chamber. Pressing the first push-button advances the lead chamber causing the lead to advance. Pressing the second push-button advances the eraser chamber causing the eraser to advance.
Another mechanical pencil is provided which includes an arrangement for holding a lead, a first push-button for advancing the arrangement for holding the lead, an arrangement for holding an eraser, and a second push-button for advancing the arrangement for holding the eraser. Pressing the first push-button advances the arrangement for holding the lead causing the lead to advance. Pressing the second push-button advances the arrangement for holding the eraser causing the eraser to advance.
A pen is provided which includes a barrel, a pen chamber, an eraser chamber, and an eraser push-button. The barrel includes a pen-end, an eraser-end, and an outer surface.
The pen chamber is situated in the pen-end and holds the pen point. The eraser chamber is situated in the eraser-end and holds an eraser. The eraser push-button is situated on the outer surface and is coupled to the eraser chamber. Pressing the eraser push-button advances the eraser chamber causing the eraser to advance.
A method for operating a mechanical pencil is provided which includes pushing a first push-button to advance a lead in a lead advance direction out a pencil nozzle and pushing a second push-button to advance an eraser in an eraser advance direction out an eraser nozzle. The lead is retracted by depressing the first push-button and applying pressure to a tip of the lead projecting out the pencil nozzle. The pressure is applied in a direction opposite the lead advance direction. The eraser is retracted by depressing the second push-button and applying pressure to a tip of the eraser projecting out the eraser nozzle. The pressure is applied in a direction opposite the eraser advance direction.